A few things about Australian cattle dogs ......... When I was a kid , we rode push bikes around the neighborhood . gates weren’t always closed and laws and rules not as strict as they are now. one thing people knew then here in Australia , is that cattle dogs would chase and bite the bicycles tyres. that is part of their reputation. Another is many stories of people entering people’s property , say the electricity meter man , a door knocker of some sort , or in some cases a burglar. only to have the owner come home to find the poor visitor having been bailed up by the Australian cattle dog , Who then would not let them leave. So they would be begging to be saved from a fence or roof or the like when the owner got home. The blue and red healers (acd’s) well known and bred for their heal bite , were renowned for just this. sneaking around behind and giving a nip. Another thing these dogs were popular for , using their natural protective and suspicious nature is guarding the back of trades peoples utes (* like a pickup truck in Australia). I know a guy who used to surf and would leave the dog with his towel and whatever else while he was in the water while it would sit and guard it.